CA: Saw some axial ("pink")at f. 1.4 in high contrast scenes - stopped down it disappeared, as axial CA does comparing to the lateral (blue), that does not disappear stopped down, but can be removed in software.

Very low distortion - if you do not put the lens too close to the face you can shoot portraits and get this fantastic bokeh if you have a fine background.

Read at the net, that the distortion was not higher than the Nikon 24mm t/s.

Sharp at f. 1.4, but not in the corners (of course not), but the corners are sharp at f. 2.8 and the farthest corners also at f. 4.0.

Vignetting at some scenes at f. 1.4 and small at f. 2.0 - gone at f. 2.8.

This is a simply super lens for nightshooting, for concerts, for landscapes (did not see any diffraction at f. 11, and only minor at f. 13 and f. 16, so it can be stopped down with excellent results).

Also for buildings, for portraits in the field using it with DX-camera (36 mm).

This is a f. 1.4 lens, so you can get misfocus at this f.stop sometimes, but only seldom, but if the subject in the city scapes at night is a bit enlightened and contrasty it is there every time.

Not totally free for ghosting if you shoot it against a strong midday- sun, and the sun is not in the middle, but just outside the frame, but nothing at all with a weaker sun or the city lights = super.

some writes that the AF is slow. I do not agree, it is OK fast, but of course not as fast as the AF from the 200mm f/2.0 or the 70-200, which both are for sports also, so do not expect that.